Stihl KM 85 R User manual

STIHL KM 85 R Instruction Manual
Manual de instrucciones

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EManual de instrucciones
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Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2019 0458-462-8721-A. VA2.H19. 0000007890_004_GB
KM 85 R
English
1
This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.
Contents
Dear Customer,
Thank you for choosing a quality
engineered STIHL product.
It has been built using modern
production techniques and
comprehensive quality assurance.
Every effort has been made to ensure
your satisfaction and trouble-free use of
the product.
Please contact your dealer or our sales
company if you have any queries
concerning this product.
Your
Dr. Nikolas Stihl
KombiSystem 2
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 2
Approved KombiTools 6
Mounting the Loop Handle 7
Adjusting the Throttle Cable 8
Fuel 8
Fueling 9
Starting / Stopping the Engine 10
Operating Instructions 12
Cleaning the Air Filter 12
Adjusting the Carburetor 13
Spark Arresting Screen in Muffler 14
Spark Plug 15
Storing the Machine 16
Inspection and Maintenance by
User 16
Inspections and Maintenance by
Dealer 16
Maintenance and Care 17
Minimize Wear and Avoid Damage 19
Main Parts 20
Specifications 21
Maintenance and Repairs 22
Disposal 22
EC Declaration of Conformity 22

KM 85 R
English
2
In the STIHL KombiSystem a number of
different KombiEngines and KombiTools
can be combined to produce a power
tool. In this instruction manual the
functional unit formed by the
KombiEngine and KombiTool is referred
to as the power tool.
Therefore, the separate instruction
manuals for the KombiEngine and
KombiTool should be used together for
the power tool.
Always read and and make sure you
understand both instruction manuals
before using your power tool for the first
time and keep them in a safe place for
future reference.
Pictograms
All the pictograms attached to the
machine are shown and explained in this
manual.
Symbols in text
WARNING
Warning where there is a risk of an
accident or personal injury or serious
damage to property.
NOTICE
Caution where there is a risk of
damaging the machine or its individual
components.
Engineering improvements
STIHL's philosophy is to continually
improve all of its products. For this
reason we may modify the design,
engineering and appearance of our
products periodically.
Therefore, some changes, modifications
and improvements may not be covered
in this manual.
Observe all applicable local safety
regulations, standards and ordinances.
If you have not used this type of power
tool before: Have your dealer or other
experienced user show you how to
operate your machine or attend a
special course in its operation.
Minors should never be allowed to use a
power tool.
Keep bystanders, especially children,
and animals away from the work area.
When the power tool is not in use, shut it
off so that it does not endanger others.
Secure it against unauthorized use.
The user is responsible for avoiding
injury to third parties or damage to their
property.
KombiSystem
.
.
.
.
002BA530 KN
+
+
Guide to Using this Manual Safety Precautions and
Working Techniques
Special safety precau-
tions must be observed
when working with a
power tool.
Always read and and
make sure you under-
stand both instruction
manuals (KombiEngine
and KombiTool) before
using your power tool for
the first time and keep
them in a safe place for
future reference. Non-
observance of the safety
precautions may result in
serious or even fatal
injury.

KM 85 R
English
3
Lend or rent your power tool only to
persons who are familiar with this model
and its operation – do not lend of rent
your power tool without the
KombiEngine and KombiTool instruction
manuals.
The use of noise emitting power tools
may be restricted to certain times by
national or local regulations.
To operate the power tool you must be
rested, in good physical condition and
mental health.
If you have any condition that might be
aggravated by strenuous work, check
with your doctor before operating a
power tool.
Persons with pacemakers only: The
ignition system of your power tool
produces an electromagnetic field of a
very low intensity. This field may
interfere with some pacemakers. STIHL
recommends that persons with
pacemakers consult their physician and
the pacemaker manufacturer to reduce
any health risk.
Do not operate the power tool if you are
under the influence of any substance
(drugs, alcohol) which might impair
vision, dexterity or judgment.
Use your power tool only for the
applications described in the instruction
manual of the KombiTool you are using.
Do not use your power tool for any other
purpose because of the increased risk of
accidents.
Do not operate the KombiEngine without
a properly mounted KombiTool since
this may result in damage to the
machine.
Only use KombiTools and accessories
that are explicitly approved for this
power tool by STIHL or are technically
identical. It is important that you read the
chapter on "Approved KombiTools". If
you have any questions in this respect,
consult a servicing dealer. Use only high
quality tools and accessories in order to
avoid the risk of accidents and damage
to the machine.
STIHL recommends the use of genuine
STIHL tools and accessories. They are
specifically designed to match the
product and meet your performance
requirements.
Never attempt to modify your power tool
in any way since this may increase the
risk of personal injury. STIHL excludes
all liability for personal injury and
damage to property caused while using
unauthorized attachments.
Do not use a pressure washer to clean
your power tool. The solid jet of water
may damage parts of the power tool.
Clothing and Equipment
Wear proper protective clothing and
equipment.
See also notes on "Clothing and
Equipment" in the instruction manual of
the KombiTool you are using.
Transporting the Power Tool
Always shut off the engine.
Transporting by vehicle: Properly secure
your power tool to prevent turnover, fuel
spillage and damage.
See also notes on "Transporting the
Machine" in the instruction manual of the
KombiTool you are using.
Fueling
Always shut off the engine before
refueling.
Do not fuel a hot engine – fuel may spill
and cause a fire.
Open the fuel cap carefully to allow any
pressure build-up in the tank to release
slowly and avoid fuel spillage.
Fuel your power tool only in well-
ventilated areas. If you spill fuel, wipe
the machine immediately – if fuel gets on
your clothing, change immediately.
Avoid clothing that could
get caught on branches
or brush or moving parts
of the machine. Do not
wear a scarf, necktie or
jewelry. Tie up and con-
fine long hair (e.g. with a
hair net, cap, hard hat,
etc.).
Gasoline is an extremely
flammable fuel. Keep
clear of naked flames. Do
not spill any fuel – do not
smoke.

KM 85 R
English
4
This reduces the risk of unit vibrations
causing the fuel cap to loosen or come
off and spill quantities of fuel.
To reduce the risk of serious or fatal
burn injuries, check for fuel leakage. If
fuel leakage is found, do not start or run
the engine until leak is fixed.
Before Starting
Check that your power tool is properly
assembled and in good condition – refer
to appropriate chapters in the instruction
manuals.
–Check the fuel system for leaks,
paying special attention to visible
parts such as the tank cap, hose
connections and the manual fuel
pump (on machines so equipped). If
there are any leaks or damage, do
not start the engine – risk of fire.
Have your machine repaired by a
servicing dealer before using it
again.
–Use only an approved combination
of cutting attachment, deflector,
handle and harness. All parts must
be assembled properly and
securely.
–Slide control / stop switch must
move easily to STOP or 0.
–Smooth action of throttle trigger
lockout and throttle trigger – the
throttle trigger must return
automatically to the idle position.
–Check that the spark plug boot is
secure – a loose boot may cause
arcing that could ignite combustible
fumes and cause a fire.
–Never attempt to modify the controls
or safety devices in any way.
–Keep the handles dry and clean –
free from oil and dirt – for safe
control of the power tool.
–Adjust harness and handle to suit
your height and reach.
To reduce the risk of accidents, do not
operate your power tool if it is damaged
or not properly assembled.
If you use a shoulder strap or full
harness: Practice removing and putting
down the machine as you would in an
emergency. To avoid damage, do not
throw the machine to the ground when
practicing.
See also notes on "Before Starting" in
the instruction manual of the KombiTool
you are using.
Start the engine.
Start the engine at least 3 meters from
the fueling spot, outdoors only.
Place the unit on firm ground in an open
area. Make sure you have good balance
and secure footing. Hold the unit
securely. The attachment must be clear
of the ground and all other obstructions
because it may begin to run when the
engine starts.
To reduce the risk of injury, avoid
contact with the attachment.
Do not drop start the power tool – start
the engine as described in the
instruction manual. Note that the
attachment continues to run for a short
period after you let go of the throttle
trigger – flywheel effect.
Check idle speed setting: The
attachment must be stationary when the
engine is idling with the throttle trigger
released.
To reduce the risk of fire, keep hot
exhaust gases and hot muffler away
from easily combustible materials (e.g.
wood chips, bark, dry grass, fuel).
See also notes on "Starting / Stopping
the Engine" in the instruction manual of
the KombiTool you are using.
Holding and Controlling the Power Tool
Always hold the power tool firmly with
both hands on the handles.
Make sure you always have good
balance and secure footing.
Left hand on loop handle, right hand on
control handle, even if you are left-
handed.
After fueling, tighten
down the fuel tank cap as
securely as possible.
002BA273 KN

KM 85 R
English
5
During Operation
In the event of impending danger or in
an emergency, switch off the engine
immediately by moving the slide control
/ stop switch to STOP or 0.
The correct engine idle speed is
important to ensure that the attachment
stops moving when you let go of the
throttle trigger. If the attachment
continues to move when the engine is
idling, have your dealer check the
machine and make proper adjustments
or repairs. Check and correct the idle
speed setting regularly. STIHL
recommends an authorized STIHL
servicing dealer.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
To reduce the risk of accidents, take a
break in good time to avoid tiredness or
exhaustion.
Work calmly and carefully – in daylight
conditions and only when visibility is
good. Stay alert so as not to endanger
others.
Use your power tool only for those
applications described in the KombiTool
instruction manual.
To reduce the risk of serious or fatal
injury from breathing toxic fumes,
ensure proper ventilation when working
in trenches, hollows or other confined
locations.
To reduce the risk of accidents, stop
work immediately in the event of
nausea, headache, visual disturbances
(e.g. reduced field of vision), problems
with hearing, dizziness, deterioration in
ability to concentrate. Apart from other
possibilities, these symptoms may be
caused by an excessively high
concentration of exhaust gases in the
work area.
Operate your power tool so that it
produces a minimum of noise and
emissions – do not run the engine
unnecessarily, accelerate the engine
only when working.
To reduce the risk of fire, do not smoke
while operating or standing near your
power tool. Note that combustible fuel
vapor may escape from the fuel system.
The dusts, vapor and smoke produced
during operation may be dangerous to
health. Wear a suitable respirator in very
dusty or smoky conditions.
If your power tool is subjected to
unusually high loads for which it was not
designed (e.g. heavy impact or a fall),
always check that it is in good condition
before continuing work – see also
"Before Starting". Check the fuel system
in particular for leaks and make sure the
safety devices are working properly. Do
not continue operating your power tool if
it is damaged. In case of doubt, consult
your servicing dealer.
Do not operate your power tool in the
starting throttle position – engine speed
cannot be controlled in this position.
Before leaving the power tool
unattended: Shut off the engine.
To reduce the risk of injury, always shut
off the engine before changing the
KombiTool or attachment.
Vibrations
Prolonged use of the power tool may
result in vibration-induced circulation
problems in the hands (whitefinger
disease).
No general recommendation can be
given for the length of usage because it
depends on several factors.
The period of usage is prolonged by:
–Hand protection (wearing warm
gloves)
–Work breaks
Your power tool produces
toxic exhaust fumes as
soon as the engine is
running. These fumes
may be colorless and
odorless and contain
unburned hydrocarbons
and benzol. Never run
the engine indoors or in
poorly ventilated loca-
tions, even if your model
is equipped with a cata-
lytic converter.

KM 85 R
English
6
The period of usage is shortened by:
–Any personal tendency to suffer
from poor circulation (symptoms:
frequently cold fingers, tingling
sensations).
–Low outside temperatures.
–The force with which the handles
are held (a tight grip restricts
circulation).
Continual and regular users should
monitor closely the condition of their
hands and fingers. If any of the above
symptoms appear (e.g. tingling
sensation in fingers), seek medical
advice.
Maintenance and Repairs
Service the machine regularly. Do not
attempt any maintenance or repair work
not described in the instruction manual.
Have all other work performed by a
servicing dealer.
STIHL recommends that you have
servicing and repair work carried out
exclusively by an authorized STIHL
servicing dealer. STIHL dealers are
regularly given the opportunity to attend
training courses and are supplied with
the necessary technical information.
Only use high-quality replacement parts
in order to avoid the risk of accidents
and damage to the machine. If you have
any questions in this respect, consult a
servicing dealer.
STIHL recommends the use of original
STIHL replacement parts. They are
specifically designed to match your
model and meet your performance
requirements.
To reduce the risk of injury, always shut
off the engine before carrying out any
maintenance or repairs or cleaning the
machine. – Exception: Carburetor and
idle speed adjustments.
Do not turn the engine over on the
starter with the spark plug boot or spark
plug removed unless the slide control /
stop switch is on STOP or 0 since there
is otherwise a risk of fire from
uncontained sparking.
To reduce the risk of fire, do not service
or store your machine near open flames.
Check the fuel filler cap for leaks at
regular intervals.
Use only a spark plug of the type
approved by STIHL and make sure it is
in good condition – see "Specifications".
Inspect the ignition lead (insulation in
good condition, secure connection).
Check the condition of the muffler.
To reduce the risk of fire and damage to
hearing, do not operate your machine if
the muffler is damaged or missing. –
Do not touch a hot muffler since burn
injury will result.
Vibration behavior is influenced by the
condition of the AV elements – check the
AV elements at regular intervals.
The following STIHL KombiTools may
be mounted on the KombiMotor:
Approved KombiTools
KombiTool
1) the barrier bar on the loop handle
supplied with the machine must be
used – see also "Mounting the Loop
Handle"
Application
FS-KM Brushcutter with
mowing head
FS-KM 1) Brushcutter with
grass cutting blade
FSB-KM Brushcutter with
mowing head
HL-KM 145° Long reach hedge
trimmer, adjustable
HL-KM 0° Long reach hedge
trimmer
FH-KM 145° Power scythe
BG-KM Blower
HT-KM Pole Pruner
BF-KM Cultivator with pick
tines
FCB-KM Edger
FCS-KM Edger
SP-KM Special harvester
KB-KM Bristle brush
KW-KM PowerSweep

KM 85 R
English
7
A barrier bar is supplied with the
machine. Attach the barrier bar to the
loop handle.
NInsert square nuts (1) in the barrier
bar (2) – the holes must line up
NInsert the clamp (3) in the loop
handle (4) and position them
together on the shaft (5)
NPosition clamp (6)
NPosition barrier bar (2) – note
position!
NLine up the holes
NInsert bolts (7) in the holes – and
screw them into the barrier bar as
far as possible
NFit the loop handle (4) at a distance
of (A) approx. 20 cm (8 in) forward
of the control handle (8)
NOrient the loop handle
NTighten the bolts – lock the nuts if
necessary
The sleeve (9) is present depending on
the country and must be located
between the loop handle and control
handle.
Always leave the barrier bar attached.
Mounting the Loop Handle
2
002BA098 KN
1
1
5
4
002BA099 KN
2
3
67
A
9
8
4
002BA353 KN

KM 85 R
English
8
A properly adjusted throttle cable is the
precondition for correct operation in the
starting throttle, idle and full throttle
positions.
Adjust the throttle cable only when the
machine is completely and properly
assembled.
NUse a suitable tool to push the slide
to the end of the slot (see
illustration).
NPress down the trigger lockout (1)
and squeeze the throttle trigger (2)
(full throttle position) – this sets the
throttle cable correctly.
Your engine requires a mixture of
gasoline and engine oil.
WARNING
For health reasons, avoid direct skin
contact with gasoline and avoid inhaling
gasoline vapor.
STIHL MotoMix
STIHL recommends the use of STIHL
MotoMix. This ready-to-use fuel mix
contains no benzol or lead, has a high
octane rating and ensures that you
always use the right mix ratio.
STIHL MotoMix uses STIHL HP Ultra
two-stroke engine oil for an extra long
engine life.
MotoMix is not available in all markets.
Mixing Fuel
NOTICE
Unsuitable fuels or lubricants or mix
ratios other than those specified may
result in serious damage to the engine.
Poor quality gasoline or engine oil may
damage the engine, sealing rings, hoses
and the fuel tank.
Gasoline
Use only high-quality brand-name
gasoline with a minimum octane rating
of 90 – leaded or unleaded.
Gasoline with an ethanol content of
more than 10% can cause running
problems in engines with a manually
adjustable carburetor and should not be
used in such engines.
Engines equipped with M-Tronic deliver
full power when run on gasoline with an
ethanol content of up to 25% (E25).
Engine Oil
If you mix the fuel yourself, use only
STIHL two-stroke engine oil or another
high-performance engine oil in
accordance with JASO FB, JASO FC,
JASO FD, ISO-L-EGB, ISO-L-EGC or
ISO-L-EGD.
STIHL specifies STIHL HP Ultra two-
stroke engine oil or an equivalent high-
performance engine oil in order to
maintain emission limits over the
machine’s service life.
Mix Ratio
STIHL 50:1 two-stroke engine oil: 50
parts gasoline to 1 part oil
Examples
NUse a canister approved for storing
fuel. Pour oil into canister first, then
add gasoline and mix thoroughly.
Adjusting the Throttle Cable
002BA163 KN
2
1
002BA161 KN
Fuel
Gasoline STIHL engine oil 50:1
Liters Liters (ml)
1 0.02 (20)
5 0.10 (100)
10 0.20 (200)
15 0.30 (300)
20 0.40 (400)
25 0.50 (500)

KM 85 R
English
9
Storing Fuel
Store fuel only in approved safety-type
fuel canisters in a dry, cool and safe
location protected from light and the sun.
Fuel mix ages – only mix sufficient fuel
for a few weeks work. Do not store fuel
mix for longer than 30 days. Exposure to
light, the sun, low or high temperatures
can quickly make the fuel mix unusable.
STIHL MotoMix may be stored for up to
2 years without any problems.
NThoroughly shake the mixture in the
canister before fueling your
machine.
WARNING
Pressure may build up in the canister –
open it carefully.
NClean the fuel tank and canister
from time to time.
Dispose of remaining fuel and cleaning
fluid properly in accordance with local
regulations and environmental
requirements.
Preparations
NBefore fueling, clean the filler cap
and the area around it to ensure that
no dirt falls into the tank.
NPosition the machine so that the
tank cap faces up.
Filling Up with Fuel
Take care not to spill fuel while fueling
and do not overfill the tank. STIHL
recommends you use the STIHL filler
nozzle for fuel (special accessory).
NOpen the tank cap.
NFill up with fuel.
WARNING
After fueling, tighten down the filler cap
as securely as possible by hand.
Fueling
389BA031 KN

KM 85 R
English
10
Controls
1Throttle trigger lockout
2Throttle trigger
3Slide control
Positions of slide control
4STOP-0– engine off – ignition is
switched off
5F– normal run position – the engine
is running or can start
6START – ignition is switched on –
the engine can start
Symbol on slide control
7h – stop symbol and arrow. To stop
the engine, push the slide control in
the direction of the arrow on the stop
symbol (h) to STOP-0.
Starting
NPress down the trigger lockout lever
and squeeze the throttle trigger
Nand hold them in that position.
NMove the slide control to START
and hold it there.
NNow release the throttle trigger,
slide control and trigger lockout in
that order. This is the starting
throttle position.
NSet the choke lever (8) to:
NPress the manual fuel pump
bulb (9) at least five times – even if
the bulb is filled with fuel.
Cranking
NPlace the power tool on the ground
so that it rests on the machine
support: Check that the working tool
is not touching the ground or any
Starting / Stopping the
Engine
3
STOP
2
5
6
4
7
002BA181 KN
START
STOP-
1
gif the engine is cold
efor warm start – also use this posi-
tion if the engine has been running
but is still cold.
393BA017 KN
8
8
393BA018 KN
9
552BA014 KN
552BA015 KN

KM 85 R
English
11
other obstacles – see also "Starting
/ Stopping the Engine" in the
KombiTool instruction manual.
NMake sure you have a safe and
secure footing.
NHold the unit with your left hand and
press it down firmly – your thumb
should be under the fan housing.
NOTICE
Do not stand or kneel on the drive tube.
NHold the starter grip with your right
hand.
NPull the starter grip slowly until you
feel it engage and then give it a brisk
strong pull.
NOTICE
Do not pull out the starter rope all the
way – it might otherwise break.
NDo not let the starter grip snap back.
Guide it slowly back into the housing
so that the starter rope can rewind
properly.
NContinue cranking.
When engine begins to fire
NSet the choke lever to e.
Ncontinue cranking.
As soon as the engine runs
NBlip the throttle trigger immediately.
The slide control moves to the
normal run position F – and the
engine settles down to idle speed.
WARNING
Make sure the carburetor is correctly
adjusted. The working tool must not
move when the engine is idling.
Your machine is now ready for
operation.
Stopping the Engine
NPush the slide control in the
direction of the arrow on the stop
symbol (h) to STOP-0.
At very low outside temperatures
As soon as the engine runs:
NBlip the throttle trigger to disengage
the starting throttle position. The
slide control moves to the normal
run position F – and the engine
settles down to idle speed.
NOpen the throttle slightly.
NWarm up the engine for a short
period.
If the engine does not start
Choke Lever
If you did not move the choke lever to e
quickly enough after the engine began to
fire, the combustion chamber is flooded.
NSet the choke lever to e .
NSet the slide control, interlock lever
and throttle trigger to the starting
throttle position.
NStart the engine by pulling the
starter rope briskly – 10 to 20 pulls
may be necessary.
If the engine still does not start
NMove the slide control to STOP-0.
NRemove the spark plug – see
"Spark Plug".
NDry the spark plug.
NCrank the engine several times with
the starter to clear the combustion
chamber.
NRefit the spark plug – see "Spark
Plug".
NMove the slide control to START.
NSet the choke lever to e – even if
the engine is cold.
NNow start the engine.
Throttle cable adjustment
NCheck adjustment of throttle cable –
see chapter on "Adjusting the
Throttle Cable".
Fuel tank run until completely dry
NAfter refueling, press the manual
fuel pump bulb at least five times –
even if the bulb is filled with fuel.
NSet the choke lever to suit the
engine temperature.
NNow start the engine.
552BA016 KN

KM 85 R
English
12
During break-in period
A factory-new machine should not be
run at high revs (full throttle off load) for
the first three tank fillings. This avoids
unnecessary high loads during the
break-in period. As all moving parts
have to bed in during the break-in
period, the frictional resistances in the
engine are greater during this period.
The engine develops its maximum
power after about 5 to 15 tank fillings.
During Operation
After a long period of full throttle
operation, allow the engine to run for a
short while at idle speed so that engine
heat can be dissipated by the flow of
cooling air. This protects engine-
mounted components (ignition,
carburetor) from thermal overload.
After Finishing Work
Storing for a short period: Wait for the
engine to cool down. Empty the fuel tank
and keep the machine in a dry place,
well away from sources of ignition, until
you need it again. For longer out-of-
service periods – see "Storing the
Machine".
Dirty air filters reduce engine power,
increase fuel consumption and make
starting more difficult.
Your power tool comes standard with
either a clip-on or screw-mounted filter
cover.
If there is a noticeable loss of engine
power
NSet the choke lever to g.
On the clip-on filter cover:
NPress in the tab (1) and swing the
filter cover (2) away.
On the screw-mounted filter cover:
NLoosen the screw (3) and remove
the filter cover (2).
On both versions:
NClean away loose dirt from around
the filter.
NRemove the foam and felt filter
elements.
NWash the foam element in a clean,
non-flammable solution (e.g. warm
soapy water) and then dry.
NFit a new felt element – do not wash.
As a temporary measure you can
knock it out on the palm of your
hand or blow it out with compressed
air.
Replace any damaged parts.
Operating Instructions Cleaning the Air Filter
355BA014 KN
2
1
3
392BA046 KN
2

KM 85 R
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13
NFit the foam filter element (4) in the
filter cover.
NPlace the felt element (5) (lettering
facing inwards) in the filter
housing (6).
NFit the filter cover.
NClip the filter cover in position or
tighten down the screw firmly.
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
adjust the high speed and low speed
screws within fine limits.
Standard Setting
NShut odd the engine.
NMount the KombiTool complete with
working tool or cutting attachment.
NCheck the air filter and clean or
replace as necessary.
NCheck that the throttle cable is
properly adjusted – readjust if
necessary – see chapter on
"Adjusting the Throttle Cable".
NCheck the spark arresting screen
(not in all versions) and clean or
replace as necessary.
NTurn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
NTurn the low speed screw (L)
carefully clockwise as far as stop,
then turn it back 1 turn.
NStart and warm up the engine if
necessary.
NAdjust idle speed with the idle speed
screw (LA) so that the cutting
attachment does not move.
Fine Tuning
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude, sea level or
after changing the working tool.
2
4
392BA047 KN
56
392BA048 KN
Adjusting the Carburetor
265BA024 KN
LA
HL
1
3 / 4

KM 85 R
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14
Rule of thumb:
Turn the high speed screw (H) about
one quarter turn for every 1000m
change in altitude.
Conditions for adjustment
NCarry out standard setting on low
speed screw (L).
NWarm up the engine for about 3
minutes.
NOpen the throttle wide.
At high altitude
NTurn the high speed screw (H)
clockwise (leaner), no further than
stop, until there is no further
noticeable increase in engine
speed.
At sea level
NTurn the high speed screw (H)
counterclockwise (richer), no further
than stop, until there is no further
noticeable increase in engine
speed.
It is possible that maximum engine
speed may be reached with the standard
setting in each case.
Adjusting Idle Speed
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
NWarm up the engine for about 3
minutes.
Engine stops while idling
NTurn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly – the working tool or
cutting attachment must not move.
Cutting attachment runs when engine is
idling
NTurn the idle speed screw (LA)
counterclockwise until the working
tool or cutting attachment stops
moving and then rotate the screw
another 1/2 to 1 turn in the same
direction.
WARNING
If the working tool or cutting attachment
continues to run when the engine is
idling, have your machine checked and
repaired by your servicing dealer.
Erratic idling behavior, engine stops
even though setting of LA-screw has
been corrected, poor acceleration
Idle setting is too lean
NIdle setting is too lean: Rotate the
low speed screw (L) about 1/4 turn
counterclockwise until the engine
runs and accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
NRotate the low speed screw (L)
about 1/4 turn clockwise until the
engine runs and accelerates
smoothly.
In some countries the muffler is
equipped with a spark arresting screen.
If the engine is down on power, check
the spark arresting screen in the muffler.
NLift the spark arresting screen and
pull it out.
NClean the spark arresting screen. If
the screen is damaged or heavily
carbonized, fit a new one.
NRefit the spark arresting screen.
Spark Arresting Screen in
Muffler
392BA035 KN

KM 85 R
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15
NIf the engine is down on power,
difficult to start or runs poorly at idle
speed, first check the spark plug.
NFit a new spark plug after about 100
operating hours – or sooner if the
electrodes are badly eroded. Install
only suppressed spark plugs of the
type approved by STIHL – see
"Specifications".
Removing the Spark Plug
NMove the slide control to STOP-0.
NPull off the spark plug boot (1).
NUnscrew the spark plug.
Checking the Spark Plug
NClean dirty spark plug.
NCheck electrode gap (A) and
readjust if necessary – see
"Specifications".
NRectify the problems which have
caused fouling of the spark plug.
Possible causes are:
–Too much oil in fuel mix.
–Dirty air filter.
–Unfavorable running conditions.
WARNING
Arcing may occur if the adapter nut (1) is
loose or missing. Working in an easily
combustible or explosive atmosphere
may cause a fire or an explosion. This
can result result in serious injuries or
damage to property.
NUse resistor type spark plugs with a
properly tightened adapter nut.
Installing the Spark Plug
NScrew the spark plug (3) into the
cylinder and fit the boot (2) (press it
down firmly).
Spark Plug
1
393BA053 KN
000BA039 KN
A
1
000BA045 KN
3
000BA050 KN
2

KM 85 R
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16
For periods of 3 months or longer
NDrain and clean the fuel tank in a
well ventilated area.
NDispose of fuel properly in
accordance with local
environmental requirements.
NRun the engine until the carburetor
is dry – this helps prevent the
carburetor diaphragms sticking
together.
NThoroughly clean the machine – pay
special attention to the air filter.
NRemove, clean and check the
attachment. Coat metal parts with
corrosion inhibiting oil.
NStore the machine in a dry and
secure location Keep out of the
reach of children and other
unauthorized persons.
Changing the Fuel Pickup Body
Change the fuel pickup body every year:
NDrain the fuel tank.
NUse a hook to pull the fuel pickup
body out of the tank and take it off
the hose.
NPush the new pickup body into the
hose.
NPlace the pickup body in the tank.
Maintenance Work
STIHL recommends that you have
servicing and repair work carried out
exclusively by an authorized STIHL
servicing dealer.
Antivibration Element
A vibration-absorbing rubber element is
installed between the powerhead and
the drive tube. Have it checked if there
are signs of wear or a noticeable
increase in vibration levels.
Storing the Machine Inspection and Maintenance
by User
389BA032 KN
Inspections and Maintenance
by Dealer
393BA055 KN

KM 85 R
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17
Maintenance and Care
The following intervals apply to normal operating conditions only. If your daily work-
ing time is longer or operating conditions are difficult (very dusty work area, etc.),
shorten the specified intervals accordingly.
before starting work after finishing work or daily after each refueling stop weekly monthly every 12 months if problem if damaged as required
Complete machine Visual inspection (condition, leaks) X X
Clean X
Control handle Check operation XX
Air filter Clean XX
Replace X
Manual fuel pump Check X
Have repaired by servicing dealer2) X
Pickup body in fuel tank Check X
Replace XXX
Fuel tank Clean XX
Carburetor
Check idle adjustment – the working/cut-
ting attachment must not run XX
Adjust idle speed X
Spark plug Adjust electrode gap X
Replace after every 100 operating hours
Cooling inlets Visual inspection X
Clean X
Spark arresting screen1) in muffler Check XX
Clean or replace XX

KM 85 R
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All accessible screws and nuts (not adjust-
ing screws) Retighten X
Anti-vibration elements Check XXX
Have replaced by servicing dealer2) X
Safety labels Replace X
1) not in all versions, market-specific
2) STIHL recommends an authorized STIHL servicing dealer.
The following intervals apply to normal operating conditions only. If your daily work-
ing time is longer or operating conditions are difficult (very dusty work area, etc.),
shorten the specified intervals accordingly.
before starting work after finishing work or daily after each refueling stop weekly monthly every 12 months if problem if damaged as required